I've got the same thing but fortunately the lines are only at the top and are about the same size as the font.
For example if there is a 2" high (white) caption at the bottom of the screen there will be very thin white lines, very close together like a barcode, at the very top of the screen matching the length (width) of the words. If there is a space in the caption, there will be a space in the white lines. Thankfully, they are ghost like so they are easy to ignore.
Note: It can also happen with bright colored graphics.
